The girls were described as best friends, popular and adventurous. Shortly before the trip, Baird updated her Facebook status: "3 Friends, 3 Bikes, 500 Miles. Let's Do This."

Dremmer was killed and Baird and Tammen were seriously injured when the van driven by an 86-year-old Enfield, Illinois man crossed the centerline of the road while going around a curve and hit the girls riding in the opposite direction. All three were seniors at University of Chicago Lab School.

"This is a moment of great sadness for the lab community," said spokesman Steve Kloehn. "It's a heartbreaking loss. Lab and the university are doing all they can to support the families involved and the whole lab community."

"[She was] conscious enough to sort of flutter her eyelids and lift her fingers," her father told the paper Thursday morning.

He said Baird suffered a broken collar bone and broken ribs.

Dremmer was especially talented in math and science and active in tennis and dance, school counselor Patty Kovacs said. Her appreciation for service to others led her at one point to donate her hair to Locks for Love, the charity that makes wigs for children who have lost their hair due to a medical condition.

"Faith Dremmer was one of the students that brought sunshine into my day and to all of her teachers' day everyday of her life," she said.

The girls had been planning the trip for months as a way to celebrate their upcoming graduation from high school. All three were wearing helmets at the time of the accident.

The driver of the car was not injured. Police are investigating the incident.